Method of and apparatus for effecting continuous distillation



Jan. 30, 1923. 1,443,742

F. M. HESS.

METHOD oF AND APPARATUS FOR EFFl-:cTrNG CONTINUOUS DISTILLALTION.

FILED MAY 8. 1919. 3 SHEETS-SHEET I den? Exc/zanja* 4 w f# CHI?? 6'0/1 ease/1 Ilm -iff/7605.5

Jan. 30, 1,443,742

METHOD oF AND APPARATUS FOR EFFECTING CONTINUOUS DlfsT ILLATIDN.

F. M. HESS.

3 .SHEETS-SHEET 2 FILED MAY 8,

3 SHEETS-SHEET 3 F. M. HESS.

Fl LED MAY 8,

METHOD o|= AND APPARATUS FOR EFFECTING CONTINUOUS Dl sT LLATloN Jan. 30, 1923.

22 ,Y VJ f 274% l FRANCIS M. HESS, 0F CHICAGO, ILLINOIS./

s METHOD OF AND APPARATUS. FOR EFFECTING CONTINUOUS DISTILLATION.

Application led May y8, 1919. Serial No. 295,527.

To all whom t may concern.'

Be it known that I, FnANois M.. Hass,

a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Methods of and Apparatus for Effecting Continuous Distillation, of which the following is a specification.

This invention `relates to a new and improved method of, and apparatus for, effecting the continuous distillation of hydrocarbon materials such as coal tar and petroleum, and their` distillates. A long felt want in continuous distillation systems has been for one that will not only release the vapors formed, and in turn condense them, before they rise too far above their own vaporizing points, but that will also afford a desirable transfer of latent heat from the products fractionated to the materials in process of heating.

The objection to raising the temperatures of the vapors too far above their own vaporizing points lies in the fact that they will either become permanent gases that are hard`- to condense, or they will unite with other gases of higher vaporizing points and form undesirable distillate products.

It is necessary, therefore, in planning a desirable routing scheme for liquids undergoing distillation, to provide one that will not only afford an ideal heat transfer system-but will also release and condense the vapors as fast as they are formed. 1

With these desirable objects in view, I

` have evolved the method and apparatus for effecting continuous fractional distillation forming the subjet matter of this invention; and I will now proceed to a detailed description rof the same in connection with the accompanying drawings wherein I have illustrated one practical and efficient form of apparatus in which the mechanical features of the invention may be embodied, and by the use of which my novel method or a process of distillation may be carried out.

I may here remark that the present invention has been so designed as to preferably, although not exclusively, make use of superheated steam as a heating agent in the boilers or vapor boxes of the system; and in the apparatus herein disclosed I have illustrated a heating equipment adapted to the use of superheated steam, although it should be. understood that in the broader aspects of the invention t-he use of superheated steam is optional and not essential.

Referring to the drawings,--

Fig. l is a diagrammatic view of a complete distillation plant embodying my i11- vention;

Fig. 2 is a similar view as seen from the right of Fig. 1, the heatv exchangers being omitted for the sake of clearness;

s Fig. 3 is an enlarged vertical section through one of the vapor boxes;

Fig. 4 is a horizontal section on the olfset line 4-4 of Fig. 3;

Fig. 5 is a' vertical section through one of the heat exchangers;

Fig. 6 is a longitudinal section through one of the vapor condensers;

Fig. 7 is an enlarged cross-section through one of the vapor condensers;

Fig. 8 is a front elevation, partly in longitudinal vertical section, of the overflow trough of the vapor box;

Fig. 9 shows a modified form of heating plate.

'Referring iirst to Figs. l and` 2, A, A', A2 and A3 represent a series of vapor boxes in which the material treated is subjected to heat for' the purpose of driving off the distillates which are released at different temperatures. B, B B2 and B3 represent a series of condensers that are connected by pipes C, C', C2 and C3 with the respective vaporboxes; each condenser, as herein shown, comprising a group of three condensing units connected in series 4by pipes c.

D, D", D2 and D3 indicate a corresponding series of-heat exchangers which are interposed in alternating relationy between a leveling tank E and the first vapor-box A and between the remaining vapor-boxes of the series, by means of inflow and outflow pipes F, F', F2, F3 and G, G, G2 and G3, respectively. H designates a residuum tank connected with the bottom ofthe lowermost vapor-box A3 by a pipe I.' K indicates a residuum pump that is connected on its 1ntake side through `pipe L with the residuum tank H and on its discharge side through pipe 'M with the bottomof the lowermost D3 of the series of heat exchangers; it being here noted thattlie heat exchangers are super-posed on each other and connected top to bottom by short pipe lengths N. From the top of the uppermost heat exchanger D a discharge pipe O conducts the residuum to any suitable or desired place of delivery.

P designates the discharge pipe from the irst condenser B; P designates the discharge pipe from the second condenser Bf P2 designates the discharge pipe from the third condenser B2; and P3 designates the discharge pipe from the fourth or last condenser B3.

Q designates a pipe constituting in part the supply line for t-he crude material drawn from any convenient source.

gro-up of condenser units B; a convenient form of condenser unit being illustrated in Figs. 6 and 7, and consisting of a drum 10 having hollow heads 11 and 12 connected by tubes 13. 14 and 15 designate a pair of baffle plates extending in opposite directions from the inner walls of the hollowl heads 12 and 11, respectively, nearly but not quite to the opposite end, thereby producing a zigzag route or passageway for the vapors while undergoing condensation, the vapors entering at the top by t-he pipe C, C, C2 or C3, passing from each unit of the group to the next through connectinu pipes c and passing off through pipe P, P2 or P3 to its point of collection.

The sup ly line from the pipe Q continues throng t-he hollow head 11, the tubes 13, the hollow'head 12, and the connecting tube Q to the next condenser unit of the group, thence through another connecting tube g to the topmost unit of the group, thence through a connecting pipe Q to the lowermost of the group of condensers B', through these and Connecting pipe Q2 to and through the next group of condensers B2, thence through connecting pipe Q3 to and through the lowermost group of condensers B3; thence by pipe Q4 into the upper end of the leveling tank E. From the latter the material flows byl gravity alternately through the heat exchangers and the vaporboxes, passing first through the uppermost heat exchanger D, thence through vaporbox A, where the most volatile vapors are driven off, thence through heat exchanger D. thence through the second vapor-box A. where the next most volatile products are driven off, thence through the third heat ex- Ichanger D2 and thence through the third vapor-box A2 where the still heavier vapors are driven off, thence through the last heat exchanger D3, and finally through the fourth orl last vapor-box A3. Fig. 5 illustrates in vertical section a preferred form of heat exchanger consisting simply of a vertical drum 16 having lower and upper hollow heads 17 and 18 and a-series of straight connecting tubes 19 between said heads. From the lowerinost vapor-box the residuum flows through pipe I into the residuum tank H where, in a highly heated condition, itXis forcedby the pump K upwardly through the series of heat exchangers D3, D2, DI

` This pipe4 leads into one end of the lowermost of the and D, passing through them successively in the order named. As the material treated flows from the leveling tank to the first vapor-box and from each vapor-box to the next through one of these heat exchangers, it picks up a large mount of latent heat in the residuum, carrying it on into the next vapor-box and to that extent utilizing heat that would otherwise pass off andl be wasted with the residuum.

Similarly, the passage of the cold crude material through the condensers has the double advantage of condensing the vapors and transferring the latent heat of the latter to the crude material, so that by t-he time the latter reaches the leveling tank it has absorbed a large amount of heat. I

It will be understood thatany desired number of units, whether of vapor-boxes, condensers or heat exchangers, may be employed in the system, and the crude material may pass through any or all of the condensers or through any or all of the heat exchangers as may be found desirable or necessary in practice.

In Figs. 3 and 4 I have illustrated somewhat in detail desirable structural characteristics of the boiler or vapor-box. As herein shown, this comprises an outer rectanglar box-like housing or casing consisting of stationary to-p and bottom walls 20 and 21, stationary opposed side walls 22, and laterally removable opposed side walls 23 which are normally united to the side walls 22 `by angle beams 24 and bolts 25. Within this casing or housing is a zigzag conduit for the flow of the material to be distilled through the vapor-box. This conduit is made up of hollow flat inclined plates or walls 26 and 27 that are connected at their proximate ends by curved walls 26 and 27',

respectively, of the same hollow formation. Each complete series of walls'26 and 27 is of zigzag or W-form, the twoV series being` internested and the zigzag conduit for the flow of the material to be distilled being between them. These walls may be cellular castings as indicated in Fig. 4, or, as indicated in Fig. 9, they may consist of steel plates28 united at intervals by rivets 29 so as to' 4provide a structure capable of resisting the internal pressure of the superheated steam flowing therethrough. The lower and upper walls 27 are provided with leads 3() and 31 extending through one of the side walls 23, and the lower and upper walls 26 are provided with similarleads 32 and 33 extending through the opposite side wall 23, these leads on adjacent vapor-boxes united by connections 34, so that. thel hollow steam conducting walls of the conduits of' lOl 35 and 36, respectively, at each side, thev two pairs of frames being connected by tie-rods 37 on which the inclined walls 26 and 27 rest, as clearlypshown in Fig. 3. On the lower ends ofthe frames 35 and 36 are wheels 38 traveling on a pair of rails 39 forming a track-way. At one upper. corner of the housing is an over-flow trough 4() (Fig. 8) preferably iformed with a serrated upper edge 40 on its front wall to distribute the material, into which trough the material is first introduced and from which it overflows onto the broad inclined top wall or plate 26 of the conduit, dropping from the end of the latter onto the topmost wall 27,`

porizing temperatures of the latter `are reached in the course of the material. Of course, the t'opmost vapor-box is the coolest of the series and the lowermost vapor-box is the hottest, so that the most easily formed vapors pass off from the topmost yvapor-box while those forming at higher temperatures are discharged from the lower vapor-boxes. Whenever it becomes necessary to disassemble one of the boilers or vapor-boxes, this is very easily done by disconnecting the connections 34, removing certain .of the bolts 25 at the corners of the structure, and then drawing the side walls 23 with the conduit wall and their supports laterally apart.

' Ashereinbefore stated, the heating element preferably used herein is superheated4 steam. This affords a gaseous heating medium that i'seasy to regulatetto any desirable temperature;`it is also positive in its action its temperature can be varied on short notice; it heats the liquid in all parts of the vapor-box uniformly, and no hotter than desired; it can be operated at any desired pressure; and by running the superheated steam counter-current to the flow of the liquid through the vapor-'box the liquid is constantly increasing in temperature; and

by running the heating medium upwardlyl from vapor-box to vapor-box in a direct-ion opposite to the flow of the liquid, the latter is heated in desirable .successive steps. In

a word, there 'is nothing desirable in opera# tion or control that is not possible of attainment with the use-of superheated steam as the heating agent.

The described construction o'fboiler or vapor box affords the following advantages.

one above another they material Hows by its own gravity in a downward course through the" several boxes, thus affording a constant pressure. 4In flowing in a broad thin stream over the heated plates of the zizag conduit it is Amost-advantageously .and uniformly subjected to the heat of the heating medium, and in falling from'plate to plate it is successively atomized to release vapors` There isample space between the. edges of the plates and the walls lof the casing or housing to allow the vapors to immediately rise and .pass off through the vapor line;

kand the construction ofthe vapor-boxes is such that the entire structure may be disassembled for repairs andcleaning, when necessary, with a minimum of time and labor. Furthermore, with the vdescribed construction of vapor-box, andthe material "residuum from becoming pocketedv`and plugging the orifices. The units are preferably set one upon another as shown in 'such fashion that they are all constantly full'and the residuum is constantly in motion in an upward direction. Preferably the heat exchanger units are so disposed relatively to the vapor-boxes that the Inaterial inpassing from box to box must flow through the units of the heat exchangers in its downwar'd direction, ,thus successively taking the heat from the residuum, the heat transfer thus being made at the most desirable points.

The type of condenser herein shown for the distillate products is not essential, but is well adapted to take the heat from the vapors as fast as they come over and is so constructed as to allow the' crude material to absqrb this heat on its way to the leveling tank and vapor-boxes. Of course, one

.or more condensers may be used for each vapor-box, as desired. Preferably` and as shown,the condensers are so constructed that the crude material will always be traveling in ayn\ opposite direction tothat of the vapors;

I do not conne the invention to the exact routing of materials shown in the drawings. The.y construction being based onthe multiple principle 'I may employ as many or lseveral condensers is controlled by the tem` perature to which the final residuum is heated. In cases Where this is extremely high it will be found that the crude material Will be heated too high by going through all the condensers before reaching the leveling tank. This would necessitate re-routing to suit the residuum temperature acquired and also the temperature desired at the first vapor-box.

The system is also such that several residuums of different consistencies may obviously be taken off at the same time if desired.

It is also noted that the system may be operated with the vapors coming from the vapor-box under the pressure caused by the gravity of the material; it may be operated with a partial vacuum in the vapor line; or it may be operated With a pressure greater than that caused by the gravity of the material.

The arrangement is Such that, regardless of What pressure the system is operated under, the material is traveling from vaporboX to vapor-box in successive steps, heat being transferred from condensers, exchangers and plates of the vapor-box in the proper sequence of degrees of heat. With the continued riseof temperature of the material, the vapors evolved at different temperatures pass over into the vapor line and through. the condensers. This vnot only affords fa practice producing results lalmost identical With the best results obtained in the old style still, When properly operated, as far as fractionating of distillates is concerned, vlout in addition the process is continuous, no part ofv the process of distillation, so that the addition of moisture to the distillates, that in many cases is hard to extract, is avoided.

I claim: Y

l. In a method of efecting'continuous distillation, the steps or operations which consist in causing the fractional distillates to flow from a series of vapor-boxes through a corresponding series of condensers, causing the crude material to flow through the said condensers out of contact lwith said distillates successively from the coolest to the hottest of said condensers, causing the crude material to How from the last of said condensers alternately through the units of said series of vapor-boxes and a series of heat exchangers from t-he coolest to the hottest, and causing the residuum from the last of said vaporboxes to flow successively through said heat exchangers.

2. In an apparatus for effecting continuous distillation, the combination of a series of vapor-boxes, a series of condensers connected to the respective vapor-boxes, a supply line for the crude material leading through said condensers into the first of said vapor-boxes, a series of heat exchangers interposed in alternating relation between and connected into said vapor-boxes, and a dischargeA line for the residuum leading from the last of said vapor-boxes through said heat exchangers. l 3. In an apparatus vfor effecting continuous distillation, the combination of a series of vapor-boxes arranged to permit a gravity flow of the crude material successively therethrough, a series of condensers connected to the respective vapor-boxes, a supply line for the crude material leading through said condensers into the highest of said vapor-boxes, a series of heat exchangers interposed in alternating relation between and connected into said vapor-boxes, and a discharge line for the residuum leading from the lowest of said vapor-boxes through said heat eX- changers.

FRANCIS M. HESS. 

